Digestion and analysis apparatus and method



April 13, 1965 A. FE JR 3,178,265

DIGESTION AND ANALYSIS APPARATUS AND METHOD Filed May 25, 1961 4Sheets-Sheet 1 I n I 1 I, r

64 56 so 36 a s8 s4 40 BYWG,Q

April 13, 1965 A. FERRARI, JR 3,178,265

DIGESTION AND ANALYSIS APPARATUS AND METHOD Filed May 25, 1961 4Sheets-Sheet 2 INVENTOR. 4%?

April 13, 1965 A. FERRARI, JR 3,173,265

DIGESTION AND ANALYSIS APPARATUS AND METHOD Filed May 25, 1961 4Sheets-Sheet 3 1440965 Eve/1 1 am c2112.-

April 13, 1965 A. FERRARI, JR 3,173,255

DIGESTION AND ANALYSIS APPARATUS AND METHOD Filed May 25, 1961 4Sheets-Sheet 4 INVENTOR. 1400/95; IZ- A I A TTQP/YEY United StatesPatent 3,178,265 DIGESTION AND ANALYSIS APPTUS AND METHGD AndresFerrari, in, Scarsdale, N.Y., assignor to Technicon instruments(Corporation, (Ihauneey, N.Y., a corporation of New York Filed May 25,1961, Ser. No. 112,590?

9 Claims. (Cl. 233-430) The present invention relates to a continuousdigestion method and apparatus which, while useful for various purposes,is intended primarily for performing Kjeldahl types of total or partialnitrogen determinations In my prior US. Patent No. 3,020,130, issuedFebruary 6, 1962, there is disclosed a method and apparatus fordigesting substances under investigation in a con tinuous manner andtreating the digested substances for analysis. As described in saidpatent, prior to my invention, Kjeldahl type of nitrogen determinationswere performed on one sample at a time in a discontinuous or batchprocess and required, for each determination, com plicated and expensiveapparatus and procedures and the use of many articles of glassware andauxiliary apparatus. present invention, in performing nitrogendeterminations, the material whose nitrogen content is to be determinedand an acid, for example sulfuric acid, for digesting the material areintroduced in the form of a liquid stream into the inlet end of ahorizontal rotary vessel. The liquid is transmitted through the rotarymember to its outlet end and is heated during its passage through saidmember. A stream of the liquid containing the digested material iswithdrawn from the rotary member at its out let end while liquid isbeing introduced into the'rotary member at its inlet end and thewithdrawn liquid is diluted with water. The diluted digested material istreated with an alkali, for example sodium hydroxide, which neutralizesthe acid content of the liquid contain ing the digested material andliberates ammonia which immediately goes into solution in the waterforming am monium hydroxide. The quantity of the ammonia, in the form ofammonium hydroxide, is used as a measure of the nitrogen in the sampleintroduced into the rotary member. The liquid containing ammoniumhydroxide is treated with alkaline phenol and sodium hypochlorite whichproduces a blue color in proportion to the quan' tity of the ammoniapresent in the liquid and the blue color of the liquid stream ismeasured by a colorimeter of the flow cuvette type. It will beunderstood that the digestion of the material and its subsequenttreatment for analysis is accomplished in a continuous fashion incontrast to the discontinuous or batch process employed heretofore inKjeldahl type of nitrogen determinations.

Pursuant to the present invention, the method and apparatus embody theprinciples disclosed in my above mentioned application and representfurther develop ments thereof in respect to certain features and formsof construction. 1

, The invention will be more fully understood from the followingdescription of the presently preferred forms of the invention consideredin connection with the accompanying drawings which are to be consideredas illustrative of the invention but not in limitation thereof.

In the drawings:

FIG. 1 is a front elevational view of a digestion apparatus according tothe present invention with portions cut away for the purposes ofillustration;

FIG. 2 is a top plan view of the apparatus;

According to my prior patent and pursuant to the 3,i?3,2h5 FatenteelApr. 113, 1365 ice FIG. 6 is a vertical sectional view, on a largerscale, of I a portion of the apparatus taken in line 6--6 of FIG. 2;

FIG. 7 is an'end view looking in the direction of arrowlofFIG. 6; f

FIG. 8 is a sectional view taken on line 8. 8 of FIG. 1; r I

FIG. 9 he more or less diagrammatic view illustrative of the method andapparatus of the present invention;

FIG. 10 is a view of part of the apparatus on an en: larged scale;

FIG. 11 is a vertical sectional view of part of the apparatus showing amodification;

FIG. 12 is a sectional view taken on line 22-12 of FIG. 11;

FIG. 13 is a vertical sectional viewshowing another modification of apart of the apparatus; and

FIG. 14 is a more or less diagrammatic view of part of the apparatusillustrating another form of the invention.

Referring now to the drawings in detail and particularly to FIGS. 1 to10, the digestion apparatus 10 comprises a liquid heating or digestioncylinder 12 which is mounted for rotation about a horizontal'axis in aheating oven 14. The oven is mounted on the op of a housing 15 whichcontains a motor 16 for rotating the digestion cylinder, heatingcontrols 18, temperature indicating meter 20, and various other controlsof the apparatus. The digestion cylinder is provided with a helicalgroove 22 along its inner surface coaxial with the axis of rotation ofthe cylinder so that the liquid which is supplied to the cylinderthrough its open inlet end 24 is caused to flow through the tube inContact with the inner surface of the lower portion of the tube to theopen outlet end 26.

During the flow of the liquid through the helical passage provided bygroove 22, the lower portion only of the cylinder is heated by theelectrical resistant heaters 28 which are disposed below and slightlyspaced from the lower portion of the digestion cylinder, as best seen inFIGS. 1 and 8. The heaters comprise a series'of heatingrods 30 whichextend longitudinally of the digestion cylinder and are symmetricallypositioned about the vertical axis of the cylinder below its lowerportion. As herein shown, there is a total of nine heating rods 30comprising a first group of three rods positioned near the inlet end 'ofthe cylinder and two other groups of three rods positioned,respectively, at the center and near the outlet end of thecylinder. Thefirst group of rods are operated together to provide a relatively highheatingtemperature at the inlet end of the cylinder and the remainingsix rods are operated together to provide a somewhat lower heatingtemperature for the remaining portions of the digestion cylinder since agreater heating is required at the inlet end of-the cylinder. The endsof the heating rods 39 are supported in'brackets 32 and extendingbetween the ends of the rods are reflectors 34 which are supported onbrackets 36 that are secured to the top 38 of housing 16. Brackets 36also support the. heater brackets 32. The undersurface, of eachreflector is covered with an insulating layer 40 of a suitable material,

for example asbestos.

It is to be observed that the lower portion only of thedigestioncylinder 12 is heated by the heating rods 36 and it is thisportion of the, cylinder whose inner surface is covered by the liquidwhich is being conveyed through the helical passage of the cylinder dueto its rotation. In this regard, it will be understood that thequantities of liquids which flow into and out of the cylinder are soregulated that the liquid flows only as a helical stream in the helicalpassage during rotation of the cylinder whereby mixing of successiveportions of the liquid stream during its flow through the passage isprevented so that contamination of one portion of the stream by apreceding portion of a dilferent sample is prevented.

.The ends of the digestion cylinder 12 extend outwardly beyond theadjacent ends of, the oven 14, and each end of the cylinder is providedwith a pair of clamping plates 42 which engage the outer surface of thecylinder to permit mounting of the rollers 44 on said extending ends ofthe cylinder. The drive for rotating the cylinder comprises a pinion 46which is connected to the shaft of motor 16, a gear 48 engaged with saidpinion, and a roller 50 which ismounted on the same shaft as gear 48 isand is provided with a peripheral groove 52 which the companion roller44 engages. The motor and gear drive are provided at the inlet end ofthe apparatus and only the companion rollers 44, 50 are provided at'theoutlet end of the apparatus. The grooved rollers 50 are connected toeach other by a horizontal'rotary shaft 54. A grooved idler roller 56 isprovided at each end of the apparatus and engages the correspondingroller 44 for supporting the cylinder in its horizontal position. Theupper half of the oven 14 is provided with a hinged transparent cover 58to which a handle 60 is secured so that the, cover may be readily openedand the digestion cylinder easily removed from the apparatus.

The open inlet end 24 of the cylinder 12 is enclosed by an inlet cap 62(FIGS. 1, 6 and 7) which is supported by a spring clip 63 which isconnected to a bracket 64 that is connected to housing 15 and it is tobe observed that the cap surrounds the inlet end of the cylinder and isspaced therefrom so as not to interfere with the rotation of thecylinder. The cap is provided with a plug 66 which supports an inlettube 68 whose outlet end 70 is in communication with an endlesscylindrical groove 72 provided at the inlet end of the cylinder 12perpendicular to the axis of rotation of the cylinder. This groove 72 isin liquid communication with the helical groove 22 so that liquid istransmitted from the groove through the helical passage of the cylinder12 by rotation of said cylinder. The cap is provided with a vent outlet74 for the exhaust of fumes from the digestion cylinder 12 which resultsfrom the digestion operation and the lower portion of the cap isprovided with a liquid outlet 76 for draining any liquid which maydeposit in the bottom of the inlet cap.

The helical passage 22 of the'digestion cylinder extends fromcylindrical groove 72 to the open outlet end 26 of the cylinder so thatthe liquid is conveyed by the rotation of the cylinder through said openoutlet end. An' outlet end cap 78 (FIGS. 1, 4 and encloses the outletend of the cylinder and is supported on the side of the housing by aspring clip 63 and bracket 64 in a manner similar to the describedsupport for the inlet cap 62. The lower portion 82 of the end cap. isfunnel-shaped and receives the liquid which flows from the outlet end 26of the cylinder. .An overflow liquid outlet 84 is provided in the funnelabove its outlet end 86. The outlet end cap is also provided with a fumeexhaust 88 which includes a tube 90 which extends endwise through theopen end 26'of the cylinder 12 for exhausting fumes from said cylinderthrough tube 92. The end caps are preferably made of glass and it willbe understood that the digestion cylinder 12 is also preferably made of,a glass which is highly resistant to heat.

The fume outlets of the end caps are connected by suitable tubing 93(FIG. 2) to the ends 94, respectively, of a fume exhaust manifold 96which is connected to an aspirator 98 via tube 106, as indicated in FIG.9. The aspirator is of a well known type which is operated by means of astream of water for withdrawing the fumes resulting from the heating ofthe acid in cylinder 12 and for diluting the acid constituents of thefumes sutficiently to produce a weak acid solution which may safely betransmitted through the outlet 102 of the aspirator for disposal in awaste pipe.

The operation of the digestion apparatus 10 will now be more fullydescribed with respect to FIG. 9 which shows the apparatus with aseparate liquid receiving funnel 104 in lieu of the integral funnel andend cap'78 previously described. The successive samples which are to. beinvestigated or analyzed in accordance with the present invention aresupplied to the pump tube 106 of a proportioning pump 168 from a samplesupply device 110 which comprises a horizontal rotary plate 112 andmounts a series of receptacles or cups 114 for the different samples,the cups being preferably. arranged in a circular row. Plate 112 isintermittently rotated and an off-take tube 116 is connected to the pumptube 106 and is pivotally moved in timed relation to the intermittentrotation of plate 112 for moving its inlet end into and out of each ofthe receptacles 114 in succession during the dwell periods of the plate.This supply device 110 may be of the construction shown and described inUS. Patent No. 3,038,340, issued June 12, 1962.

The proportioning pump 108, which is schematically illustrated, may beof any suitable type although it is preferablyof the type described .inUS. Patent No. 2,935,028, issued May 3, 1960. Briefly described, the

r pump comprises a plurality of resiliently flexible tubes which arecompressed progressively along their lengths for the pumping operationby the engagement therewith of a plurality of pressure rollers whichmove longitudinally of the pump tubes to fully close said tubesprogressively along their lengths and thus propel the liquids or otherfluids for transmitting them from sources of supply to points ofdelivery.

As herein shown, the sample to be digested is transmitted by the pumptube 106, the acid is transmitted by the pump tube 118 and air or otherinert gas is transmitted by the pump tube 120. The fluids mix with eachother at fitting 122 and form a segmented stream consisting of a seriesof liquid segments containing the sample and the acid separated by aseries of intervening gas segments. The segmented stream passes througha horizontal glass helical mixing coil 124 wherein the constituents ofeach liquid segment are mixed together and the segmented stream istransmitted from the mixing coil, via conduit 126, to the inlet tube 68,which is connected to the conduit, for introducing the acid and sampleinto the digestion cylinder 12. The air segments of the introducedstream escape from the digestion cylinder through the fume vent 74. Theprovision of the intervening segments of gas help maintain the tubularpassages of the apparatus clean to avoid contamination of one liquidsample by a preceding liquid sample. The proportioning pump is operatedcontinuously so that when the off-take aspirating tube 116 of the samplesupply device 110 is not immersed in the liquid in the cups 114, air istransmitted through the off-take tube as well as through tube and asacid is being continuously supplied through pump tube 118 due to thecontinuous action of the pump, each succeeding sample is separated fromthe other by an intervening air-segmented stream of acid wherebycontamination of one sample by a preceding sample is eliminated orreduced to a tolerable degree. It is to be observed that due to theoperation of the sample supply device 110 and pump 108, a series ofseparate liquid samples and a stream of acid are introduced into thedigestion cylinder 12 during spaced intervals of time and a stream ofacid without said liquid samples is introduced into the cylinder betweensaid spaced intervals of time.

As the cylinder rotates, the introduced liquid stream is transmittedfrom the peripheral groove 72 and flows progressively in the helicalgroove 22 in contact with the inner surface of the lower portion of thecylinder longitudinally of the cylinder through its open outlet end 26and into the funnel 104. In the'course of the passage of the liquidthrough the digestion cylinder 12 the digestiblematerial in the samplewhich is being investigated or analyzed is digested by the heated acidand is in a highly concentrated condition by the time it reaches theoutlet end 26 of the cylinder. The outlet end 86 of the end cap 78 or ofthe funnel 104 is connected to conduit 128 which is connected to a pumptube 130 and the liquid is transmitted through said conduit and pumptube by the action of the pump to fitting 132 where it joins a stream ofair or other inert gas which is introduced through pump tube 134 andsubdivides the liquid stream into a series of liquid segments spacedfrom each other by intervening gas segments. It will be understood thatpump tube 13%} is made of a resiliently flexible material highlyresistant to the heated concentrated acid nature of the digestedmaterial. A suitable material, for example, is sold under the trademarkFluran 5000 and is manufactured by the US. Stonewall Co. of Akron, Ohio.Further description of the pump tube 13% and its material is notconsidered necessary as it does not, per se, form part of the invention.The use of special material for pump tube 13d can be avoided by dilutingthe digested material before it reaches the pump as shown in FIGS. 11,13 and 14, which will be explained hereinafter. i

A diluent, for example, water, is introduced into the segmented streamvia pump tube 136 and the diluted segmented stream is then cooled bypassing through the cooling coil 138 which is immersed in a watercooling bath 140. Since the liquid contains sulfuric acid in a highlyconcentrated condition, only a relatively small quantity of water isadded to the liquid and after it has been cooled an additional quantityof water is added to the liquid through pump tube 142 and the resultingmixture is passed through an air-cooled helical mixing coil 144. Anadditional quantity of water is added through pump tube 146 and theresulting mixture is mixed in another air cooled helical mixing coil148. The nature of the resulting diluted and cooled liquid is such as tohave no serious detrimental effects on the parts and tubes of theapparatus. The cooling effect provided by the coolers 140, 144 and 148reduces the quantity of diluent required to a minimum so that theapparatus performs with a high degree of sensitivity.

The diluted liquid is then transmitted through conduit 159 and pump tube152, respectively, to a fitting 154- where it mixes with air and sodiumhydroxide which are introduced through pump tubes 156 and 15 8,respectively. As explained above, the air serves to segmentize theresulting liquid stream which consists of liquid segments containing thedigested liquid and sodium hydroxide. The constituents of the liquidsegments of the stream are mixed together in a helical mixing coil 16%and from the helical mixing coil, the mixed segmentized liquid streamjoins a stream of a liquid containing alkaline phenol, one of thesubstances of the above-described color reagent, which is introducedthrough pump tube 162. The resulting stream is transmitted to a mixingcoil 164 and the other of the above described color reagents, namelysodium hypochlorite, which is introduced through pump tube 1-56, joinsthe mixed stream from mixing coil 1(4 and the resulting liquid stream ismixed in mixing coil 163. From coil 16 3 the liquid passes to theheating bath 176 wherein the color is fully developed and from saidheating bath the liquid passes through the cooling coil 172; and thenthrough the flow cuvette of a colorimeter 174 which operate a recorder175 for recording the results of the color measurement. Since thedetails of construction of the colorimeter and recorder are not per separt of the invention, a further description of these instruments isconsidered unnecessary. The measured liquid is discharged from the flow'cuvette of the colorimeter through outlet 176.

As described above, acid fumes are removed by suction from the open endsof the cylinder 12 and are thus prevented from contaminating the air inthe workroom or laboratory, said acid fumes being diluted with water anddischarged to waste through the outlet ltlZ of the asp-irator 9'8. Also,as indicated above, the overflow outlet 84 of the funnel 194 dischargesany excess liquid which rises to the level of said overflow outlet.

The method and apparatus of the present invention can be used forpartial digestion of a substance under investigation when said substanceis homogeneous, ie when it has only one source of nitrogen in itscomposition. In this connection, it will be understood that totaldigestion is employed in accordance with a well known practice when thesubstance is not homogeneous, i.e. when it includes more than one sourceof nitrogen in its composition and the rates of digestion of saidnitrogen sources are not relatively the same. Also it will be understoodthat while the method and apparatus of the present invention areintended primarily for performing Kjeldahl types of quantitativeanalysis with respect to the nitrogen content of a substance, theprinciples of the method and apparatus of the present invention are notlimited to such determina tions, and may be used for other punposes.

Referring now to FIGS. 11 and 12, there is shown a modification of theoutlet end of the digestion apparatus 19 wherein the digested materialis aspirated from the digestion cylinder 12 in lieu of being transmittedthrough the open outlet end 26 of the cylinder to a funnel 82 which isintegral with an end cap 78, as shown in FIG. 4 for example, or in lieuof being transmitted to a separate funnel 1164, as shown in FIG. 9. Morespecifically, an outlet end cap 178 is provided, enclosing the openoutlet end 25 of the digestion cylinder and is provided with a plug 18dwhich supports a liquid off-take tube 182 and a liquid inlet tube 134which supplies a diluent, for example water, to the digested materialwhile said material is in the digestion cylinder. The diluent reducesthe detrimental nature of the hot concentrated acid and eliminates thenecessity of special pump tubing material, as explained previously. Theout-let end of the digestion cylinder is provided with cylindricalgrooves 185, herein shown as two, connected to each other by the helicalgroove 22, and each groove is in liquid-flow communication with thehelical groove 22 and is provided with projecting vanes or mixingmembers 186 for mixing the digested material and the diluent introducedthrough inlet tube 184. Grooves 135 are at right angles to the axis ofrotation of the cylinder 1-2. The outlet end 1-37 of the inlet tube ispositioned in the groove upstream of the inlet end 11% of the oft-taketube 182 and is adjacent to groove 185 in which end 188 of the ofi-taketube is positioned or may be spaced one or more turns upstream from saidinlet end. The inlet end of the off-take tube is preferably positionedvclose to the bottom of the groove adjacent the end 26 of the digestioncylinder. Tubes 182 and 184 are connected by suitable conduits to pumptubes of the proportioning pump Hi8 so that during the operation of thepump the diluting liquid is introduced into the digestion cylinderthrough tube 184 and the mixed digested material and diluent areaspirated from the digestion cylinder through tube 182 and from thelatter to the cooling bath 14%? which may be accomplished by connectingthe aspirating tube 182 to conduit 128. In this case, if desired or itnecessary, pump tube 136 may be eliminated. The end cap 173 is providedwith the previously described fume exhaust outlet 92 and overfiowdrainoutlet 34.

In FIG. 13 there is shown another form of the outlet end cap. As hereshown, the outlet end cap 1% includes a plug 192 which supports threetubes, namely, an inlet tube 194 for introducing a diluent into thedigestion cylinder, as previously described, an aspirating or off-taketube 196 for aspir-ating liquid from the cylinder and an overfiow tube198 for aspirating excessive liquid from the cylinder. The digestioncylinder 12' is similar to the di- 'gestion cylinder previouslydescribed with respect to FIG. 11 but has, in addition, an endlesscylindrical groove 200 at the outlet end of the cylinder which is inliquid communication with the helix 22 and is perpendicular to thehorizontal axis of the cylinder. The groove 20%) has a greater volumethan a groove of the helix or groove 185 and acts as a reservoir orliquid receiver into which the digested liquid and diluent is introducedfrom the helix. The inlet end 262 of the overfiow tube is above theinlet end 204 of the off-take tube 196. Tube 198is connected to one ofthe pump tubes (not shown) of the proportioning pump so that it isapparent that when the liquid rises in groove 209 to the level of inletend 262, the overflow tube 198 aspirates the excessive liquid from thedigestion cylinder. It is to be observed that since diluent is beingadded to the digested mixture, the quantity of the liquid in thedigestion cylinder at its outlet end is greater than that at its inletend and groove 200 provides a reservoir for this excessive liquid. Withrespect to the end cap 178, as shown in FIGS. 11 and 12, the overflowoutlet 84 removes any excessive liquid which may occur due to theintroduction of the diluent at the outlet end of the cylinder. End cap190 is also provided with the previously described fume exhaust outlet92.

Referring now to FIG. 14, there is also shown a modification of theinvention which permits the introduction of the diluting water into theliquid containing the digested material before said material istransmitted through the pump and in this manner eliminates the necessityof providing special acid-resistant pump tubes resistant to theconcentrated acid nature of the liquid, as previously mentioned. Asshown in FIG. 14, the liquid flows from the outlet 86 of the funnel 104and water is added to the outflowing liquid through pump tube 206 andconduit 2458 and the diluted liquid is passed through the water cooledmixing coil 138. Additional Water is supplied through pump tube 210 andconduit 212 and is added to the outfiowing cooled diluted liquid frommixing coil 138 and the resulting liquid is transmitted through the aircooled mixing coil 144- and the liquid from said mixing coil is mixedwith additional Water supplied through pump tube 214. The resultingliquid is mixed in air cooled mixer 148 and thereafter is transmitted tothe previously mentioned pump tube 152 for subsequent treatment, aspreviously described. It will be observed that before the digestedmaterial is transmited to any of the pump tubes, it has been dilutedwith Water and cooled so that when it arrives at the pump it is nolonger in a condition which may have adverse effects on the pump tubesor other parts of the apparatus.

While I have shown and described the preferred embodiment of myinvention, it will be understood that the invention may be embodiedotherwise than as herein specifically illustrated or described, and thatcertain changes in the form and arrangement of parts and the specificmanner of practicing the invention may be made Without departing fromthe underlying ideas or principles of this invention within the scope ofthe appended claims.

What is claimed is:

1. Continuous liquid-treatment and analysis apparatus, comprising ahorizontally mounted longitudinally extending rotary member having meansdefining a helical passage therein disposed coaxially of the axis ofrotation of said member for the flow of liquid therein from a point ofliquid supply to a liquid-delivery point downstream from said point ofsupply, means for rotating said member about said axis for the flow ofthe liquid in said helical passage to said point of delivery, means forheating said member during its rotation whereby to heat the liquid,means during spaced intervals of time into said rotary member at saidpoint of liquid supply for treatment in said memher, during the flow'ofsaid samples to said point of delivery, means for introducing a reagentliquid into said rotary member at a point upstream of said liquiddelivery point for treating said liquid samples while said samples flowin said member toward said delivery point, said reagent being heatedduring its flow in said member whereby the samples are subjected to theaction of said heated reagent liquid, during the flow toward saiddelivery point, means for introducing a diluent into said rotary memberat a point upstream from said liquid delivery point and downstream fromsaid reagent delivery point, means for receiving the diluted liquid fromsaid rotary member in the form of a stream containing the treated liquidsamples spaced from each other longitudinally of the stream by otherintervening, liquid, and means for treating the treated liquid samplesin said last mentioned stream during the fiow thereof for examination inrespect to a particular substance therein.

2. Continuous liquid-treatment and analysis apparatus, comprising ahorizontally mounted longitudinally extending rotary member having meansdefining a helical passage therein disposed coaxially of the axis ofrotation of said member for the flow or" liquid therein from a point ofliquid supply to a liquid-delivery point'downstream from said point ofsupply, means for rotating said member about said axis for the how ofthe liquid in said helical passage to said point of delivery, means forheating said member during its rotation whereby to heat the liquid,means operable to introduce a series of separate liquid samples duringspaced intervals of time into said rotary member at said point of liquidsupply for treatment in said member, during the flow of said samples tosaid point of delivery, means for introducing a reagent liquid into saidrotary member at a point upstream of said liquid delivery point fortreating said liquid samples while said samples flow in said membertoward said delivery point, said reagent being heated during its flow insaid member whereby the samples are subjected to the action of saidheated reagent liquid during the flow toward said delivery point, meansfor introducing a diluent into said rotary member at a point upstreamfrom said liquid delivery point and downstream from said reagentdelivery point, means for receiving the diluted liquid from said rotarymember in the form of a stream containing the treated liquid samplesspaced from each other longitudinally of the stream by other interveningliquid, means for treating the treated liquid samples in said lastmentioned stream during the flow thereof for examination in respect to aparticular substance therein, and analysis means including a colorimeterhaving a flow cuvette through which said stream of treated samples andintervening liquid between said treated samples is transmitted for saidexamination of said treated samples.

3. Continuous liquid-treatment and analysis apparatus, comprising ahorizontally mounted longitudinally extending rotary member having meansdefining a helical passage therein disposed coaxially of the axis ofrotation of said member for the flow of liquid therein from a point ofliquid supply to a liquid-delivery point downstream from said point ofsupply, means for rotating said memher. about said axis for the flow ofthe liquid in said helical passage to said point of delivery, means forheating said member during its rotation whereby to heat the liquid,means operable to introduce a series of separate liquid samples duringspaced intervals of time into said rotary member at said point of liquidsupply for treatment in said member, during the flow of said samples tosaid point of delivery, said rotary member having an outlet opening atsaid delivery point and said helical passage extending to said outletopening whereby the liquid flows directly from said helical passagethrough said outlet opening, means for introducing a reagent liquid intosaid rotary member at a point upstream of said liquid delivery point fortreating said liquid samples while said samples flow in said membertoward said delivery point, said reagent being heated during its flow insaid member whereby the samples are subjected to-the' action of saidheated reagent liquid, during the flow toward said delivery point, meansfor introducing a diluent into said rotary member at a point upstreamfrom said liquid delivery point and downstream from said reagentdelivery point, means for receiving the diluted liquid from said rotarymember in the form of a stream containing the treated liquid samplesspaced from each other longitudinally of the stream by other interveningliquid, and means for treating the treated liquid samples in said lastmentioned stream during the flow thereof for examination in respect to aparticular substance therein.

4. Continuous liquid-treatment apparatus, comprising a heating vesselmounted for rotation about a horizontal axis, means for rotating saidvessel about said axis, means for heating said vessel during itsrotation, liquid inlet means in liquid flow communication with saidvessel for introducing a stream of liquid into said vessel during itsrotation, said vessel having a helical groove along its inner surfacecoaxial with the axis of rotation of said vessel for causing the liquidto flow in contact with the lower portion of said inner surface fromsaid inlet means to a position downstream from said inlet means, liquidoutlet means for the delivery of liquid from said vessel at saiddownstream position and while the liquid is being introduced into saidvessel through said inlet means, and means positioned upstream of saidoutlet means and downstream of said inlet means for transmitting anotherliquid to said first mentioned liquid before the latter is deliveredfrom said vessel, said vessel having projecting means extending from theinner surface of said vessel at the position of said liquid transmittingmeans for mixing said other liquid and said first mentioned liquidduring the rotation of said vessel.

5. Continuous liquid-treatment apparatus, comprising a heating vesselmounted for rotation about a horizontal axis, means for rotating saidvessel about said axis, liquid inlet means in liquid flow communicationwith said vessel for introducing a stream of liquid into said vesselduring its rotation, said vessel having a helical groove along its innersurface coaxial with the axis of rotation of said vessel with side wallsof adequate height for causing the liquid to flow in and along saidgroove between said side walls in contact with the lower portion of saidinner surface from said inlet means to a position downstream from saidinlet means, an endless cylindrical groove in liquid flow communicationwith said helical groove at said downstream position for receiving theliquid from said helical groove, said cylindrical groove having a volumewhich is greater than the volume of a turn of said helical groove,liquid outlet means in communication with said cylindrical groove fordelivering liquid therefrom and while the liquid is being introducedinto said vessel through said inlet means, means for heating said vesselduring its rotation; and means downstream of said liquid inlet means andupstream of said liquid outlet means for transmitting another liquid tosaid first mentioned liquid before the latter is delivered from saidvessel.

6. Continuous liquid-treatment and analysis apparatus, comprising aliquid-heating vessel mounted for rotation about a horizontal axis,means for rotating said vessel about said axis, liquid-inlet means inliquid flow communication with said vessel for introducing a stream ofliquid into said vessel during its rotation, said vessel having ahelical groove along its inner surface coaxial with the axis of rotationof said vessel for causing the liquid to flow in contact with the lowerportion of said inner surface from said inlet means to a positiondownstream from said inlet means, means for heating said vessel duringits rotation, liquid outlet means in liquid flow com munication withsaid vessel for the delivery of liquid from said vessel at saiddownstream position during the rotation of said vessel and while thestream of liquid is being introduced into said vessel through said inletmeans, means inliquid flow communication with said vessel posi tionedupstream of said outlet means and downstream of said inlet means fortransmitting another liquid to said first mentioned liquid before thelatter is delivered from said vessel, means for receiving from saidoutlet means and for treating the withdrawn liquid for analysis,analysis means, and means for transmitting a stream of said treatedliquid to said analysis means from said treating means. i

7. Continuous liquid-treatment and analysis apparatus, comprising aliquid-heating vesselmounted for rotation about a horizontal axis, meansfor rotating said vessel about said axis, liquid-inlet means in liquidflow communication with said vessel for introducing a stream of liquidinto said vessel during its rotation, said vessel having a helicalgroove along its inner surface coaxial with the axis of rotation of saidvessel for causing the liquid to flow in contact with the lower portionof said inner surface from said inlet means to a position downstreamfrom said inlet means, means for heating said vessel during itsrotation, liquid outlet means in liquid flow communication with saidvessel for the delivery of liquid from said vessel at said downstreamposition during the rotation of said vessel and while the stream ofliquid is being introduced into said vessel through said inlet means,means in liquid flow communication with said vessel positioned upstreamof said outlet means and downstream of said' inlet means fortransmitting another liquid to said first mentioned liquid before thelatter is delivered from said vessel, said vessel having means formixing said other liquid and said first mentioned liquid during theirpassage through said vessel, means for receiving from said outlet meansand for treating the withdrawn liquid for analysis, analysis means,and-means for transmitting a stream of said treated liquid to saidanalysis means from said treating means.

8. Continuous liquid-treatment and analysis apparatus, comprising aliquid-heating vessel mounted for rotation about a horizontal axis,means for rotating said vessel about said axis, liquid-inlet means inliquid flow communication with said vessel for introducing a stream ofliquid' into said vessel during its rotation, said vessel having ahelical groove along its inner surface coaxial with the axis of rotationof said vessel for causing the liquid to flow in contact with the lowerportion of said inner surface from said inlet means to a positiondownstream from said inlet means, means for heating said vessel duringits rotation, liquid outlet means in liquid flow communication with saidvessel for the delivery of liquid from said vessel at said downstreamposition during the rotation of said vessel and while the stream ofliquid is being introduced into said vessel through said inlet means,means in liquid flow communication with said vessel for introducing adiluting liquid into said vessel upstream from said downstream positionand downstream from said inlet means, said vessel having means formixing said diluting liquid and said first mentioned liquid during theirpassage through said vessel, means for receiving from said outlet meansfor adding liquid to said mixed liquids after their delivery from saidvessel, means coupled to said receiving means for further treating thediluted liquid mixture for analysis, analyzing means, and means fortransmitting a stream of said treated liquid to said analyzing meansfrom said treating mean-s.

9. A continuous digestion and analysis method according to which thereis provided a horizontal rotary member provided with a liquid passageextending helically around the axis of rotation of said member, saidmethod comprising rotating said member about said axis and heating saidmember during its rotation, introducing into said liquid passage at apredetermined position a stream of liquid containing the substance to bedigested and an acid 1 l l 2 for digesting said substance, introducing adiluting liquid References Cited by the Examiner. into said-liquidpassage at a position downstream from UNITED STATES PATENTS said firstmentioned position, withdrawing from said rotary v I member during therotation'thereof and at a position 222: donta to th 't' f'td g 'dd'lt' rw s re m r m e posi 10H 0 1n r0 11cm sai 1 u mg 5 3020130 2/62 Ferrari23 230 liquid a stream of the liquid containing thevdiluted digestedsubstance, regulating the quantity of said liquids which T flow into andout of said member so that the liquid flows 2 FOREIGN A ENTS' in saidhelical passage only duringthe rotation of said O4067 1/57 Francememberto prevent mixin of successive portions of the 10 liquid stream duringits- 50w through said passage, and MORRIS WOLK Primary Examiner treatingthe withdrawn liquid stream during its flow for MAURICE A. BRINDISI,ANTHONY SCIAMANNA, quantitative analysis in respect to said digestedsubstance. Examiners.

1. CONTINUOUS LIQUID-TREATMENT AND ANALYSIS APPARATUS, COMPRISING AHORIZONTALLY MOUNTED LONGITUDINALLY EXTENDING ROTARY MEMBER HAVING MEANSDEFINING A HELICAL PASSAGE THEREIN DISPOSED COAXIALLY OF THE AXIS OFROTATION OF SAID MEMBER FOR THE FLOW OF LIQUID THEREIN FROM A POINT OFLIQUID SUPPLY TO A LIQUID-DELIVERY POINT DOWNSTREAM FROM SAID POINT OFSUPPLY, MEANS FOR ROTATING SAID MEMBER ABOUT SAID AXIS FOR THE FLOW OFTHE LIQUID IN SAID HELICAL PASSAGE TO SAID POINT OF DELIVERY, MEANS FORHEATING SAID MEMBER DURING ITS ROTATION WHEREBY TO HEAT THE LIQUID,MEANS OPERABLE TO INTRODUCE A SERIES OF SEPARATE LIQUID SAMPLES DURINGSPACED INTERVALS OF TIME INTO SAID ROTARY MEMBER AT SAID POINT OF LIQUIDSUPPLY FOR TREATMENT IN SAID MEMBER, DURING THE FLOW OF SAID SAMPLES TOSAID POINT OF DELIVERY, MEANS FOR INTRODUCING A REAGENT LIQUID INTO SAIDROTARY MEMBER AT A POINT UPSTREAM OF SAID LIQUID DELIVERY POINT FORTREATING SAID LIQUID SAMPLES WHILE SAID SAMPLES FLOW IN SAID MEMBERTOWARD SAID DELIVERY POINT, SAID REAGENT BEING HEATED DURING ITS FLOW INSAID MEMBER WHEREBY THE SAMPLES ARE SUBJECTED TO THE ACTION OF SAIDHEATED REAGENT LIQUD, DURING THE FLOW TOWARD SAID DELIVERY POINT, MEANSFOR INTRODUCING A DILUENT INTO SAID ROTARY MEMBER AT A POINT UPSTREAMFROM SAID LIQUID DELIVERY POINT AND DOWNSTREAM FROM SAID REAGENTDELIVERY POINT, MEANS FOR RECEIVING THE DILUTED LIQUID FROM SAID ROTARYMEMBER IN THE FORM OF A STREAM CONTAINING THE TREATED LIQUID SAMPLESSPACED FROM EACH OTHER LONGITUDINALLY OF THE STREAM BY OTHER INTERVENINGLIQUID, AND MEANS FOR TREATING THE TREATED LIQUID SAMPLES IN SAID LASTMENTIONED STREAM DURING THE FLOW THEREOF FOR EXAMINATION IN RESPECT TO APARTICULAR SUBSTANCE THEREIN.